1993 VOLKSWAGEN CORRADO Repair Manual

G - TESTS W/CODES
Article Text (p. 3)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PMÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ TROUBLE CODE IDENTIFICATION
TROUBLE CODE IDENTIFICATION (CORRADO SLC) (1)
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄDTC (2) System/ Possible
(Blink) Code Affected Circuit Cause/Repair
00281 (1231 ......... Vehicle Speed Sensor .... Open Ckt (No Signal
From Speedometer)
00513 (2111) ....... Engine Speed Sensor ....... Open Ckt Or Loose
Or Faulty Sensor
00515 (2113) ........ Hall Effect Sensor ....... Open/Short Ckt To
Ground Or Battery
Voltage
00518 (2212) ... Throttle Valve Potentiometer .. Open/Short Ckt To
Ground Or Battery
Voltage
00522 (2312) ....... Coolant Temp. Sensor ...... Open/Short Ckt To
Ground Or Battery
Voltage
00524 (2142) ......... Knock Sensor I ...... Open Ckt Or Short Ckt
To Battery Voltage
00525 (2342) ....... Oxygen (O2) Sensor ........ Open/Short Ckt To
Ground Or Battery
Voltage
00527 (2412) .... Intake Air Temp. Sensor ...... Open/Short Ckt To
Ground Or Battery
Voltage
00532 (2234) ........ Supply Voltage ........ Battery Voltage Less
Than 10.0 Volts Or
More Than 16.0 Volts
00533 (2231) .. Idle (IAC Valve) Regulation .. Intake System Leaks
Or IAC Valve Stuck
Or Dirty
00535 (2141) ..... Knock Sensor (Primary) ........ Defective Knock
Sensor In ECM
(Replace ECM)
00537 (2341) .. Oxygen (O2) Sensor Regulation ... (3) Control Limit
Exceeded Or Not
Reached
00540 (2144) ....... Knock Sensor II .......... Open/Short Ckt (No
Signal to ECM
00543 (2214) .... Maximum RPM Exceeded .. RPM Signal Interference;
Engine RPM Exceeded
Cut-Off Point
00545 (2314) ... Engine/Transmission Signal .. Short Ckt To Ground
00553 (2324) ..... Mass Airflow Sensor ....... Short Ckt To Ground
Or Battery Voltage
00561 (2313) ... Fuel Mixture Adaptation .... ... (4) Control Limit
Not Reached Or

G - TESTS W/CODES
Article Text (p. 4)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PM
Exceeded
00585 (2411) ... EGR Temperature Sensor ...... Short Ckt To Ground
Or Faulty Sensor
00586 (----) ........ EGR Control ........ EGR Valve Sticking Open
01025 (----) .. Malfunction Indicator Light .... Open/Short Ckt To
Ground Or Battery
Voltage
01242 (4332) ...... ECM Output Stage ........ Faulty Ckt To Output
Check Controlled
Components
01247 (4343) ... EVAP Frequency Solenoid ...... Open/Short Ckt To
Ground Or Battery
Voltage
01249 (4411) ....... Injector No. 1 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01250 (4412) ....... Injector No. 2 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01251 (4413) ....... Injector No. 3 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01252 (4414) ....... Injector No. 4 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01253 (4415) ....... Injector No. 5 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01254 (4422) ....... Injector No. 6 ............ Open/Short Ckt To
Ground Or Battery
Voltage
01257 (4431) .. Idle Air Control (IAC) Valve ... Open/Short Ckt To
Ground Or Battery
Voltage
01259 (4433) ....... Fuel Pump Relay ....... Open Ckt Or Short Ckt
To Battery Voltage
01265 (4312) .. EGR Frequency (2-Way) Valve .... Open/Short Ckt To
Ground Or Battery
Voltage
65535 (1111) ... Electronic Control Module .... Replace Faulty ECM
(1) - For testing information, see J - PIN VOLTAGE CHARTS article.
(2) - Blink code is 4-digit malfunction indicator CHECK ENGINE
light code.
(3) - Check intake and exhaust systems for leaks. Check for too low
or too high a fuel pressure. Also check for malfunctioning
fuel injectors or engine misfire.
(4) - Check intake and exhaust systems for leaks. Check for mass
airflow sensor hot wire not burning off cleanly. Check for
faulty oxygen sensor control and for EVAP frequency solenoid
sticking open. Also check for malfunctioning fuel injectors or
engine misfire.

G - TESTS W/CODES
Article Text (p. 5)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PMÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ ENTERING SELF-DIAGNOSTICS
VAG ON-BOARD DIAGNOSTICS
NOTE: If VAG SELF-DIAGNOSIS (VAG ON-BOARD DIAGNOSTIC) display
does not appear on scan tester, check DLC terminals for
battery voltage and ground. Upper terminal should have
battery voltage, bottom terminals serve as ground.
Corrado SLC
1) Ensure battery voltage and fuses No. 18 and 22 are okay.
Ensure engine ground connections at cylinder head cover and at
manifold are okay.
2) Connect Scan Tester (VAG 1551) to Data Link Connectors
(DLC) located in center console, in front of shift lever. Attach Black
connector first, wait for VAG ON-BOARD DIAGNOSTIC display, then
connect White connector. DO NOT connect scan tester Blue connector.
3) Turn ignition on or start engine depending on function
being selected. See appropriate SELECTABLE FUNCTIONS table. Press "1"
button to select RAPID DATA TRANSFER function.
4) Press "0" and "1" buttons to select ENGINE ELECTRONICS
function. Press "Q" button to enter input. Electronic Control Module
(ECM) identification will be displayed on scan tester.
5) If CONTROL MODULE DOES NOT ANSWER message is displayed,
press HELP button to print a list of possible causes. With scan tester
in RAPID DATA TRANSFER function, press right arrow button. Press "02"
to "08" buttons to select desired function. Press "Q" button to enter
input.
SELECTABLE FUNCTIONS (CORRADO SLC) (1)
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄFunction Ignition On Engine On
02 (Read DTC/Fault Memory) .. ..... ............. X
03 (Output Check/
03 Diagnostic Test Mode) ...... X .......... .....
04 (Start Basic Setting) ..... ..... ............. X
05 (Erase DTC/Fault Memory) .. ..... ............. X
06 (End Output) ............... X ............... X
08 (Read Measuring Value Block) X ............... X
(1) - Press HELP button at any time to obtain additional
scan tester operating instructions.
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ OUTPUT CHECK DIAGNOSIS (OUTPUT DIAGNOSTIC TEST MODE)
NOTE: See ENTERING SELF-DIAGNOSTICS for additional scan tester
operating instructions.

G - TESTS W/CODES
Article Text (p. 6)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PM
Corrado SLC (2.8L)
1) Connect Scan Tester (VAG 1551) to Data Link Connectors
(DLC) located in center console, in front of shift lever. With scan
tester in OUTPUT DIAGNOSTIC TEST MODE, the injectors, Idle Air Control
(IAC) valve, evaporative frequency (solenoid) valve, oxygen sensor
relay, and EGR frequency valve (if equipped) may be actuated in
sequence listed.
2) The injector(s) must click by opening and closing
throttle. To trigger injectors 2 through 6, open and close throttle
once for each injector. If injector(s) do(es) not click, test
circuit(s) using the J - PIN VOLTAGE CHARTS article.
3) If injectors are okay, switch to next output test by
pressing the right arrow button. Press right arrow button to actuate
IAC valve. IAC valve must pulsate noticeably until switched to next
output test by pressing the right arrow button.
4) If IAC valve does not pulsate, turn ignition off.
Disconnect IAC valve and connect LED Tester (US 1115) to IAC valve
wiring harness connector using jumper wires from Adapter Kit (VW
1594).
5) Turn ignition on and repeat IAC valve output test. If LED
blinks, replace IAC valve. If LED does not blink, test circuit using
the J - PIN VOLTAGE CHARTS article in this section. If IAC and circuit
are okay, replace ECM.
6) If IAC valve pulsates properly, locate evaporative
frequency solenoid valve (located behind air cleaner housing, on
wheelwell). Disconnect hose, coming from fuel vapor canister, from
frequency solenoid. Attach auxiliary hose to solenoid.
7) Blow into auxiliary hose, in direction of throttle
housing, while performing solenoid output test (pressing right arrow
button to actuate evaporative frequency solenoid). If solenoid does
not actuate (open and close), disconnect wiring harness from solenoid.
Connect LED tester to solenoid wiring harness connector using jumper
wires from adapter kit.
8) Repeat evaporative solenoid valve output test. If LED
blinks, replace evaporative frequency solenoid valve. If LED does not
blink, test circuit using the J - PIN VOLTAGE CHARTS article. If
evaporative solenoid valve and circuit are okay, replace ECM.
9) If evaporative frequency solenoid operates properly, press
right arrow button to actuate oxygen sensor relay (mounted on
fuse/relay panel with a clip). If relay does not click, test relay and
its circuit using the J - PIN VOLTAGE CHARTS article.
10) If relay operates properly, press right arrow button to
actuate EGR frequency valve. Frequency valve must click until test
mode is switched to next output test by pressing the right arrow
button.
11) If frequency valve does not click, disconnect valve.
Connect LED tester using jumper wires from Adapter Kit (VAG 1594) to
frequency valve wiring harness connector.
12) If LED blinks, replace EGR frequency valve. If LED does
not blink, test circuit using the J - PIN VOLTAGE CHARTS article. If
EGR frequency valve and circuit are okay, replace ECM.
13) If EGR frequency valve operates properly, press right

G - TESTS W/CODES
Article Text (p. 7)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PM
arrow button twice to select END OUTPUT function on scan tester. Press
"Q" to enter input. Turn ignition off. Disconnect scan tester.
READ MEASUREMENT & READ MEASURING (TEST) VALUE BLOCK
NOTE: See ENTERING SELF-DIAGNOSTICS for additional scan tester
operating instructions.
Corrado SLC (2.8L)
1) Connect Scan Tester (VAG 1551) to Data Link Connectors
(DLC) located in center console, in front of shift lever. With scan
tester in READ MEASURING VALUE BLOCK function, press "01" to "06"
buttons to select desired display group. See appropriate DISPLAY GROUP
table.
2) When display group is selected, only the second number is
shown on display (the zero does not appear on display). With READ
MEASUREMENT BLOCK function completed, select END OUTPUT function on
scan tester. Turn ignition off. Disconnect scan tester.
DISPLAY GROUP (CORRADO SLC)ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄDisplay Group Number Display
& Channel Number Parameters
01
1 ..................................... Engine Speed
2 ....................... Engine Coolant Temperature
3 ............................. Oxygen Sensor Signal
4 .................................. Ignition Timing
02
1 ..................................... Engine Speed
2 ................................... Injection Time
3 ................................... System Voltage
4 .................. EGR Temperature (If Applicable)
03
1 ..................................... Engine Speed
2 ...................................... Engine Load
3 ................................... Throttle Angle
4 ............. Intake Air Temperature (At Manifold)
04
1 ..................................... Engine Speed
2 ...................................... Engine Load
3 .................................... Vehicle Speed
4 .............. Switch Positions (Operating Status)
05
1 ..................................... Engine Speed
2 ..................... Idle Air Control (IAC) Valve
3 ................................... IAC Duty Cycle
4 ............ Switch Positions (A/C & Auto. Trans.)
06
1 ............................. Oxygen Sensor Signal
2 ........... Oxygen Sensor Adaptive Learning (Idle)

G - TESTS W/CODES
Article Text (p. 8)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PM
3 .. Oxygen Sensor Adaptive Learning (Part Throttle)
4 .. Oxygen Sensor Adaptive Learning (Full Throttle)ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ CLEARING CODES
See RETRIEVING CODES.
ECM LOCATION
ECU/ECM LOCATION
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄApplication Location
Corrado .......... Below fresh air intake on firewall
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ SUMMARY
If no hard fault codes (only "sporadic" codes) are present,
driveability symptoms exist or intermittent codes exist, proceed to
the H - TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH
IDLE, NO START, etc.) or intermittent diagnostic procedures.
END OF ARTICLE

GEAR TOOTH CONTACT PATTERNS
Article Text
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PM
ARTICLE BEGINNING
GENERAL INFORMATION
Gear Tooth Contact Patterns
* PLEASE READ THIS FIRST *
The following article is for GENERAL INFORMATION purposes
only. Information does not SPECIFICALLY apply to all years, makes and
models, but is to be used as a general reference guide.
INSPECTION
PRELIMINARY INSPECTION
Wipe lubricant from internal parts. Rotate gears and inspect
for wear or damage. Mount dial indicator to housing, and check
backlash at several points around ring gear. Backlash must be within
specifications at all points. If no defects are found, check gear
tooth contact pattern.
GEAR TOOTH CONTACT PATTERN
NOTE: Drive pattern should be well centered on ring gear teeth.
Coast pattern should be centered, but may be slightly toward
toe of ring gear teeth.
1) Paint ring gear teeth with marking compound. Wrap cloth or
rope around drive pinion flange to act as brake. Rotate ring gear
until clear tooth contact pattern is obtained.
2) Contact pattern will indicate whether correct pinion
bearing mounting shim has been installed and if drive gear backlash
has been set properly. Backlash between drive gear and pinion must be
maintained within specified limits, until correct tooth pattern is
obtained.

GEAR TOOTH CONTACT PATTERNS
Article Text (p. 2)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 09:11PMFig. 1: Drive Axle Gear Tooth Patterns
ADJUSTMENTS
GEAR BACKLASH & PINION SHIM CHANGES
NOTE: Backlash is adjusted by either moving shims from one side of
differential case to the other or by turning adjusting nuts
on which side bearing races ride. Changing of pinion shims
alters the distance from face of pinion of centerline of
ring gear.
1) With no change in backlash, moving pinion further from
ring gear moves drive pattern toward heel and top of tooth, and moves
coast pattern toward toe and top of tooth.
2) With no change in backlash, moving pinion closer to ring
gear moves drive pattern toward toe and bottom of tooth, and moves
coast pattern toward heel and bottom of tooth.
3) With no change in pinion shim thickness, an increase in
backlash moves ring gear further from pinion. Drive pattern moves
toward heel and top of tooth, and coast pattern moves toward heel and
top of tooth.